I'm using a XD V55 transmitter on a guitar. I decided to make an extra chord for it. The new chord I made gives me a scratchy sound from the volume pot as it leaves 0 position. I made the solder connections cleanly and precisely with no excess solder. I'm baffled as to why the new chord has this problem and the original chord doesn't. What am I missing?

It came off my 20 year old Nady wireless transmitter. I installed the 4 pin mini XLR plug and removed the filter cap from the other end. The center wire is white. It also has a clear coating underneath this outer coating. I don't see any coating over the outer shield wire. Just the rubber outer sleeve. Maybe I should use a different chord...